Instrument and music-gear retailers on Reverb outgrow spreadsheet reconciliation fast. Every Reverb sale needs a Sales Order, stock has to drop the moment a guitar sells, listings drift out of sync with what ERPNext actually holds, and Reverb's settlement statements — with their marketplace fees, shipping labels and payout timing — never line up cleanly with your books. ERPNext ships a strong core (Sales Order, Delivery Note, Sales Invoice, Item, Bin-level stock, Payment Entry), but it has no native concept of a Reverb order, a Reverb listing, or Reverb's fee structure. That gap is where manual data entry, oversells and month-end reconciliation pain live.

The ERPNext Reverb Connector is a purpose-built Frappe app that closes that gap. We install a proper app with its own module and DocTypes — Reverb Settings (single, holding OAuth credentials and sync toggles), Reverb Order, Reverb Listing and Reverb Sync Log — plus mapping tables that link Reverb listings to ERPNext Items by SKU. A scheduler_events job polls the Reverb API on a configurable interval to pull new and updated orders, while hooks.py doc_events on Item, Item Price and Stock Ledger fire writeback to Reverb when your inventory or pricing changes in ERPNext. Whitelisted methods (@frappe.whitelist()) expose a manual "sync now" and per-listing publish/edit actions, and inbound Reverb webhooks are received on a dedicated endpoint for near-real-time order capture where your Reverb account supports them.

Under the hood, an incoming Reverb order maps to a Sales Order (and optionally an auto-created Delivery Note and Sales Invoice) against a dedicated Reverb customer or per-buyer contact, with correct taxes, currency and a stored Reverb order id for idempotency so retries never double-post. Inventory is kept in two-way sync: when ERPNext stock changes via the Stock Ledger, available quantities push up to the matching Reverb listing, and when Reverb reports a sale, the connector reserves or consumes stock in ERPNext — with configurable buffer quantities to prevent overselling across channels. Price updates flow from ERPNext Item Price to Reverb listings. When you mark a shipment in ERPNext, tracking number and carrier are written back to Reverb to fulfil the order. Settlement statements are ingested and reconciled: marketplace fees, shipping charges and payouts are booked to the accounts you nominate so your Reverb revenue ties out to actual bank deposits.

Because every Reverb store, chart of accounts and warehouse setup is different, this is build-to-order — not a one-click marketplace download. After you request a quotation we run a short scoping call, confirm exactly which flows you need (order sync, listing management, inventory direction, settlement depth), and quote a fixed scope. Typical delivery is one working week from confirmed scope. We build against Frappe/ERPNext v15 and v16, validate on a staging clone of your site through UAT, then install on production with a rollback plan, hand over the git repository and source, train your team, and back it with a post-go-live support window.